[buildbot] phase1: build local tar before running downloads

[LEDE Commits]

jow pushed a commit to buildbot.git, branch master:
https://git.lede-project.org/58d6f62aafdd86f2626fc6c71f0bd0fbe2565329

commit 58d6f62aafdd86f2626fc6c71f0bd0fbe2565329
Author: Jo-Philipp Wich <jo at mein.io>
AuthorDate: Fri Nov 4 17:54:04 2016 +0100

    phase1: build local tar before running downloads
    
    The download make target requires a modern GNU tar with --sort support in order
    to pack SCM archives.
    
    As Debian still ships an older tar, explicitely build the local tools/tar
    before invoking "make download".
    
    Signed-off-by: Jo-Philipp Wich <jo at mein.io>
---
 phase1/master.cfg | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/phase1/master.cfg b/phase1/master.cfg
index 4014c20..7e74bd3 100644
--- a/phase1/master.cfg
+++ b/phase1/master.cfg
@@ -355,6 +355,14 @@ EOT''' %(ts[0], ts[0], ts[1]) ))
 		want_stdout = False
 	))
 
+	# prepare tar
+	factory.addStep(ShellCommand(
+		name = "dltar",
+		description = "Building GNU tar",
+		command = ["make", WithProperties("-j%(nproc:~4)s"), "tools/tar/install", "V=s"],
+		haltOnFailure = True
+	))
+
 	# populate dl
 	factory.addStep(ShellCommand(
 		name = "dlrun",